Xilinx and Nujira announced the first successful integration of envelope tracking (ET) technology with a third-party digital pre-distortion (DPD) solution running on an FPGA. The two companies have delivered a reference design for a cellular base station PA circuit with Nujira’s Coolteq.h envelope tracking modulator linearized by a Xilinx DPD block running on a Xilinx Virtex 6 FPGA platform. Envelope signal generation in the FPGA was implemented using Nujira’s Envelope Generation Interface, which is compliant with the openET Alliance’s specification for infrastructure ET modulators.

“Xilinx is fully committed to supporting the cellular industry in minimizing the environmental impact and operating cost of the next generation of 3G and 4G infrastructure,” said Dave Hawke, Senior Product Marketing Manager, wireless communications at Xilinx. “Envelope tracking technology is increasingly being recognized as a must-have power optimization technology and Xilinx has therefore integrated an envelope tracking port into its 3rd generation Multimode Radio Targeted Design Platform (TDP). The combination of Nujira’s leadership in market ready envelope tracking power modulators and Xilinx’s leadership in DPD and Crest Factor Reduction (CFR) LogiCORE IP, results in the industry best power efficiency, in a low cost and highly flexible package.”

The integration was based on Nujira’s NCT-B1110 Envelope Generation Interface VHDL code integrated with Xilinx’s v4.0 Digital Predistortion LogiCORE IP block, running on a Xilinx ML605 reference platform for the Virtex 6 FPGA. A Nujira NCT-H4010 ET modulator was used with a simple FMC interface adaptor for direct connection to the ML605. The RF path was generated by Analog Devices’ AD-MSDPD-EVB Mixed Signal Digital Pre-Distortion Evaluation Platform, and the power amplifier was a Nujira NCT-T4503 power amplifier using a SEDI EGN21B090IV GaN power transistor.